Topping MA4 Review

[Nuyes]

A question - Why is there such a huge difference between the THD data of another third-party data measured in the anechoic chamber and that of this review?View attachment 469317

"Related THD(%)" is heavily influenced by the measured fundamental response curve. This is true even in so-called “anechoic” environments unless you have a system like the Klippel NFS or a truly perfect free-field setup. Anechoic chambers are also not entirely free from the effects of standing waves, so there are inherent limits below a certain reliable frequency.


In my case, I do not have access to an anechoic chamber or a Klippel NFS system, so my low-frequency measurements are inevitably affected by room modes and various reflections. For this reason, my data cannot be directly compared 1:1 with NFS measurements.

To provide readers with more useful context, I include two supplementary THD plots in my reviews:

• CHD – Calculated as the percentage of THD based on the average SPL between 200 Hz and 10 kHz.
• EHID – Normalizes the transfer function of the speaker, microphone, and room to calculate THD%. This method can yield quite accurate results as long as the speaker does not begin rolling off within the measured band. If roll-off does occur, the data can be inflated, which is why I apply different frequency ranges depending on the speaker’s response.

This approach is based on one of the measurement methods described in IEC 60268.



Furthermore, no measurement environment can achieve absolutely perfect SPL calibration, and this is another major factor that can cause variations in related THD(%) between different measurement sessions.

 

[Rmjesty]

"Related THD(%)" is heavily influenced by the measured fundamental response curve. This is true even in so-called “anechoic” environments unless you have a system like the Klippel NFS or a truly perfect free-field setup. Anechoic chambers are also not entirely free from the effects of standing waves, so there are inherent limits below a certain reliable frequency.


In my case, I do not have access to an anechoic chamber or a Klippel NFS system, so my low-frequency measurements are inevitably affected by room modes and various reflections. For this reason, my data cannot be directly compared 1:1 with NFS measurements.

To provide readers with more useful context, I include two supplementary THD plots in my reviews:

• CHD – Calculated as the percentage of THD based on the average SPL between 200 Hz and 10 kHz.
• EHID – Normalizes the transfer function of the speaker, microphone, and room to calculate THD%. This method can yield quite accurate results as long as the speaker does not begin rolling off within the measured band. If roll-off does occur, the data can be inflated, which is why I apply different frequency ranges depending on the speaker’s response.

This approach is based on one of the measurement methods described in IEC 60268.



Furthermore, no measurement environment can achieve absolutely perfect SPL calibration, and this is another major factor that can cause variations in related THD(%) between different measurement sessions.

thank you. Now I understand

 

[Sokel]

"Related THD(%)" is heavily influenced by the measured fundamental response curve. This is true even in so-called “anechoic” environments unless you have a system like the Klippel NFS or a truly perfect free-field setup. Anechoic chambers are also not entirely free from the effects of standing waves, so there are inherent limits below a certain reliable frequency.


In my case, I do not have access to an anechoic chamber or a Klippel NFS system, so my low-frequency measurements are inevitably affected by room modes and various reflections. For this reason, my data cannot be directly compared 1:1 with NFS measurements.

To provide readers with more useful context, I include two supplementary THD plots in my reviews:

• CHD – Calculated as the percentage of THD based on the average SPL between 200 Hz and 10 kHz.
• EHID – Normalizes the transfer function of the speaker, microphone, and room to calculate THD%. This method can yield quite accurate results as long as the speaker does not begin rolling off within the measured band. If roll-off does occur, the data can be inflated, which is why I apply different frequency ranges depending on the speaker’s response.

This approach is based on one of the measurement methods described in IEC 60268.



Furthermore, no measurement environment can achieve absolutely perfect SPL calibration, and this is another major factor that can cause variations in related THD(%) between different measurement sessions.

A good recommendation is also made by Steve F. Temme in "How to graph distortion measurements" presented at the 94th AES convention in March 1993.
REW has it as an option, I quote:

If Use harmonic frequency as ref is selected the reference will be the frequency of the harmonic - for example, at 1 kHz the 2nd harmonic figure will depend on the level of the fundamental at 2 kHz, the 3rd harmonic will depend on the level of the fundamental at 3 kHz and so on. This follows a recommendation made by Steve F. Temme in "How to graph distortion measurements" presented at the 94th AES convention in March 1993. If the response of the system being measured is flat this makes no difference to the results, but when the response is not flat (as for most acoustic measurements) it can remove the influence of the loudspeaker's fundamental response from the distortion figures. As an example, suppose the loudspeaker response was flat apart from a 6 dB peak at 2 kHz. 2 kHz is the 2nd harmonic of 1 kHz, so the 2nd harmonic level shown at 1 kHz will be increased by 6 dB due to the boost in the fundamental when using the excitation frequency as the reference. Similarly the 3rd harmonic level at 667 Hz (2/3 kHz) will be boosted by 6 dB. If the harmonic frequency were used as the reference the distortion figures would not show this boost. Using the harmonic frequency as the reference also provides a more meaningful view of distortion at frequencies below the LF roll-off of the system as otherwise the distortion levels are boosted as the level of the fundamental drops. Note that this option will not affect the traces when the plot is not normalised, but will still affect the values in the legend if the distortion figures are set to read in percent or in dB relative to the fundamental.

It's a nice way to address the fundamental differences.

 

[SMJ]

Design inspiration from the Meridian M3 of the 1980s, maybe?

 

[TurtlePaul]

A question - Why is there such a huge difference between the THD data of another third-party data measured in the anechoic chamber and that of this review?

Both seem to show 1% distortion up to 700 hz at 85 dB, so they aren’t that far off.

 

[Billy Budapest]

Nice try by Topping, not a consideration until the air leak issue is fully resolved. Maybe a mkII is in order?

Wasn’t an air leak issue the same kind of problem that caused all that rancor surrounding the March Audio Sointuva?

 

[milosz]

Thanks for your reviews!

As for the haters - please post a few of YOUR OWN reviews so we can see quality in action.... no? I thought not.

 

[Moravid]

Would this work well as a centre channel?

 

[LeffetheAudiophile]

Neat that Topping is diving into speakers now as well.
If there's any europeans interested in these speakers, they are now available on Audiophonics!

 

[Tovarich007]

I looked at this on Audiphonics website too.

They're sold for 449 €/pair in EU, shipping not included. That's not expensive, but there is a very hard competition out there for small good budget monitors. Other very competent and sometimes larger monitors with DSP and EQ are on the market at roughly the same price level, released by well known european, japanese or american brands.

And the measurements presented on this thread are good indeed but not exceptionnal, This model is also very deep for its averall size, that's not easy to set on many desktops.
Maybe Topping will expand its speaker lineup and propose DSP or more flexible analog versions, but at present I would rather go for a small Yamaha, Adam audio, Kali, Jbl or IK multimedia if I were searching for a new budget monitor. Both a more conservative and flexible choice.